VBS objshell.AppActivate doesn't work with Windows Task Scheduler

Hi all,

This script do the following : 

Open Adobe Flash media Live Encoder with an encoding profile

Activate the Adobe Flash... Window

Send enter key to start encoding

Set objShell = WScript.CreateObject( "WScript.Shell" )
objShell.Run """C:\Program Files (x86)\Adobe\Flash Media Live Encoder 3.2\FlashMediaLiveEncoder.exe"" /p ""C:\Users\process\AppData\Roaming\Adobe\Flash Media Live Encoder 3.2\profile.xml"""
'Loading time
WScript.Sleep 5000
objshell.AppActivate ("Adobe Flash Media Live Encoder 3.2")
WScript.Sleep 5000
objShell.SendKeys "{ENTER}" 'start encoding

This script perfectly works manually, but the objshell.appactivate command doesn't work when i run it with the windows task Scheduler.

Any ideas ? Thx